1. Field of the Invention
The invention relates to a plasma display panel of a matrix display scheme.
2. Description of the Related Art
Recent years, a plasma display panel of a matrix display scheme (hereinafter referred to as “PDP”) has been received attention as an oversized and slim display for color screen.
An AC type PDP is known as such display panels of the matrix display scheme.
The AC type PDP includes a plurality of row electrode pairs arranged on the inner face of a front substrate so that each forms a display line, and a plurality of column electrodes arranged on the inner face of a back substrate, opposing the front substrate with a discharge space between, in a direction perpendicular to the row electrode pairs. At each intersection of the row electrode pairs and the column electrodes, discharge cells form a matrix in cooperation with each other.
The row electrode pairs and the column electrodes are overlaid with dielectric layers at the respective surfaces facing the discharge space. Phosphor layers are provided on the column electrodes arranged on the inner face of the back substrate.
One of conventionally known methods of displaying a halftone on such a PDP is a so-call sub-field method in which a display period of one field is divided into N sub-fields in which light is emitted at intervals corresponding to the weight of each bit position of the N-bit display data.
In the sub-field method, each sub-field consists of a concurrent reset period Rc, an addressing period Wc and a sustain discharge period Ic as illustrated in FIG. 40.
In the concurrent reset period Rc, reset pulses RPx, RPy are concurrently applied between the row electrodes X1-n and Y1-n paired with each other to produce discharge in all the discharge cells in unison, thereby temporarily forming a predetermined amount of wall charge in each discharge cell.
In the addressing period Wc, scan pulses SP are sequentially applied to the row electrodes Y1-n each which is one of the row electrode pair, and display data pulses DP1-n corresponding to the display data in each display line are applied to the column electrodes D1-m to initiate a selective discharge (selective eraser discharge).
During this period, corresponding to the display data, all the discharge cells are grouped into the lighted cells in which eraser discharge is not caused to maintain the wall charge, and the non-lighted cells in which the eraser discharge is caused to erase the wall charge.
In the sustain light-emission period Ic, sustain pulses IPx, IPy are applied between the row electrodes X1-n, Y1-n paired with each other at intervals corresponding to the weight of each sub-field, to thereby allow the sustain discharge to be repeatedly produced in only the lighted cells, having residual wall charge, at intervals in accordance with the intervals of application of the sustain pulses IPx, IPy.
The discharge space between the front substrate and the back substrate is filled with a Ne—Xe gas containing 5 vol % xenon Xe. The sustain discharge allows radiation of 147 nm-wavelength vacuum ultraviolet rays from xenon Xe.
The vacuum ultraviolet rays excite the phosphor layers provided on the back substrate and then visible light is generated, resulting in the image display on the PDP.
In the PDP as described above, although the reset discharge in the concurrent reset period Rc of the sub-field method generates priming particles (charged particles) in the discharge space of all the discharge cells, the priming particles decrease as time goes by. Hence, the priming particles decrease in the display lines (e.g. an nth display line which forms the final scan line) in which the time interval until the next selection is operated (the scan pulses SP are applied) after the concurrent reset is operated is much longer than in the other display lines.
For this reason, in such discharge cells having a less quantity of priming particles, the discharge delay time is extended or variations of the discharge delay time are increased. This causes the selective discharge operation in the addressing period Wc to be unstable and to have a tendency to produce a false discharge, resulting in a disadvantage of loss of quality of displayed images.